Insulator-frame arrangement for an electric heater



Dec. 12, 1967 J. M. HIMES 3,358,074

INSULATOR-FRAME ARRANGEMENT FOR AN ELECTRIC HEATER Filed June 2, 1965 F/GB uo/w M Hwss Arm/war United States Patent Ofiice 3,358,fl74 Patented Dec. 12, 1967 3,358,074 INSULATCR-FRAME ARRANGEMENT FOR AN ELECTRIC HEATER John M. I-Iimes, Hartford, Wis., assignor to E. R. Wagner Manufacturing Company, Milwaukee, Wis., a corporation of Wisconsin Filed June 2, 1965, Ser. No. 460,764 11 Claims. (Cl. 174-138) ABSTRACT OF THE DISCLOSURE This disclosure relates to a combination insulator and frame support for the coil of an open coil heater. The insulator is generally cylindrical with an internal coil receiving opening and a continuous surface projecting from the outer periphery of the insulator. The projecting surface is made up of a series of alternating circumferential and axial portions, adjacent circumferential portions being axially spaced with respect to each other, alternate circumferential portions being in alignment and the axial portions extending between adjacent ends of the circumferential portions. The frame is provided with a closed rectangular portion which engages-and supports the insulator. The legs of the rectangular portion are positioned axially between the circumferential portions so that a number of the circumferential portions engage the legs on one axial side with the remainder of the circumferential portions engaging the legs on the opposite axial side to hold the insulator against axial movement. The axial portions of the continuous surface are disposed generally in the corners of the rectangular portion for engagement with the legs of the rectangular portion to prevent rotation of the insulator.

This invention relates to electric heater constructions and, more particularly, to an insulator-frame arrangement for supporting the coils of an electric heater.

A general object of this invention is to provide an improved and simplified connection of an insulator with its support frame.

Another object of this invention is to provide a connection between an insulator and its support frame which permits an insulator construction which can be readily and economically manufactured.

For the achievement of these and other objects, this invention proposes a construction wherein the insulator is provided with surfaces which are spaced about and project outwardly from the periphery of the insulator body. Portions of the frame are formed to a shape which, when engaged to support the insulator, cooperate with the projecting surfaces to prevent relative movement between the frame and insulator.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claims, as will obvious modifications of the embodiment shown in the drawings, in which:

FIG. 1 is a front elevation of a portion of an electric heater illustrating the insulator-frame arrangement for supporting an electric coil;

FIG. 2 is an end view thereof;

FIG. 3 is a sectional view taken generally along line 33 of FIG. 1;

FIG. 4 is a sectional view 44 of FIG. 2; and

FIG. 5 is a developed view of the insulator body.

This invention may find particular application in a given type of heater, for example an open coil heater as commonly used in many conventional household appliances, but it will be appreciated that it is not intended that it be limited to any particular type of heater constructaken generally along line tion or application. Moreover, since the particular heater construction, e.g. an open coil heater, is well known and is neither necessary to a complete understanding of this invention nor does it form a part of this invention, only a portion of a typical type of heater assembly is illustrated in the drawings. More particularly, the heater includes a basic frame construction 10, only a portion of which is illustrated in FIG. 1, and an insulator support or retaining member 12 which is suitably connected in and forms a part of frame 10, for example by a spot weld. Frame member 12 engages and supports insulators 14 and 16 and the insulators in turn receive electric heater coils 1S and 20 and serve to electrically insulate the coils from the frame. It will be appreciated that the heater frame includes a number of structural members such as that shown in FIG. 1 for supporting frame member 12 and these in turn may each support a member of the insulatorframe assemblies including frame member 12 and insulators 14 and 16.

In heater assemblies of this type the coil, or coils, must be reliably supported and adequately insulated from the metallic support frame with minimal engagement with the coil so as to leave the major portion of the coil exposed for effective operation, i.e. heat radiation. Therefore, to insure continued insulation the connection between the insulator and frame must be such as to prevent relative movement therebetween after assembly but the space available for this connection is limited if a maximum amount of heater surface is to be exposed for optimum heat radiation. This invention harmonizes these design considerations while also providing a simplified insulator and frame construction. More particularly, insulator 14 includes a cylindrical body 22 having an internal opening 24 for receipt of heater coil 18. A continuous radial projection 26 is provided on and extends around the outer circumference of body 22. Projection 26 is made up of a number of arcuate segments 28, 30, 32 and 34 each having a limited circumferential extension on the body periphery. structurally, segments 28 and 32 are circumferentially spaced from each other but are axially spaced from segments 30 and 34 which are in turn circumferentially spaced from each other. Insulators 14 and 16 are of identical construction and only one will be described in detail with the understanding that the description is applicable to both.

Frame member 12 is provided with end portions 36 and 37 which support the insulators and are formed to cooperate with projection 26 to prevent the insulators from becoming dislodged from the frame. Reference will be made to portion 36 but it will be noted that both end portions are identical so that the description of one a-pplies to both. Structurally end 36 includes legs 38, 40, 42 and 44 disposed at an angle to each other with leg 44 turned toward leg 38 to form a closed, generally polygonal-shaped loop for receiving insulator 14. The legs of the loop are disposed axially between arcuate segments 28-34 and the axial spacing between the segments is greater than the width of frame member 12 so that radial face 28a of segment 28 is arranged to engage and 36 (leg 44) on one axial side thereof, radial face 30a of segment 30 engages end 36 (leg 38) on the axially opposite side thereof and radial faces 32a and 34a of projections 32 and 34 similarly engage adjacent legs 40 and 42 on axially opposite sides. With this arrangement insulator 18 is held in the loop formed in end 36, will not become dislodged and provides continuous, reliable insulation between electric coil 18 and the metallic frame.

rotational movement of the insulator in end 36. Preferably rotational movement is prevented by the provision of circumferentially spaced, axially extending projections 48, 50, 52 and 54. These axially extending surfaces extend radially from the periphery of insulator 18 and preferably form a part of projection 26 and cooperate in making projection 26 a continuous'surface by extending between and connecting adjacent ends of segments 28', 30, 32 and 34. Axial projections 48-54 are relatively spaced around the periphery of the insulator in accordance with the spacing between the formed corners of'the polygonal loop of end 36 and, when assembled, the axial projections are positioned in the corners of the loop thereby being arranged for engagement with the legs of end'36 to prevent rotation of the insulator with regard to end 36. Preferably, axial projections 48 54 are spaced ninety degrees apart and end 36 is in the form of a square and, moreover, legs 3844 are preferably formed so as to extend generally tangentially with respect to the outer circumference of insulator 14 to provide a compact construction and also to cooperate in preventing rotation of the insulator within end 36.

Preferably, frame member 12. is made up of a continuous strip-like member which is formed to provide ends 36 and 37 connected by a central web 56, however, other forms are possible within the scope of this invention. In assembling insulator 14 in member 12 legs 38, 40 and 42 may be formed to provide an open U, insulator 14 inserted and leg 44 turned to complete the loop and securely position insulator 14 therein. In this regard axial projection 54 can provide a fulcrum upon which leg 44 is turned and remains in engagement in the corner to further insure securely holding the insulator in the frame member. This arrangement reliably holds the insulator in the frame with the axial and circumferential components of the continuous projection 16 preventing rotational and axial movement of the insulators in the frame while providing a compact arrangement of'insulator and frame and permitting an insulator configuration which can be readily and economically manufactured.

Although but one embodiment of'the present invention has been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

I claim:

1. An arrangement for supporting a coil of an electric heater and comprising, in combination,

a plurality of electrical insulators each having a tubular body portion including an internal coil receiving opening and external radially projecting surfaces including axially and circumferentially extending portions, said circumferentially extending portions each having a limited circumferential extension on said body portion and adjacent ones of said circumferentially extending portions spaced axially from each other and said axially extending'portions being relatively spaced from each other in a circumferential direction and extending between and'connecting the adjacent ends of said circumferential extending. portions to form with said circumferential extending portions a continuous radially projecting surface extending around the circumference of the body, and frame means includingpolygonal-shapedinsulator engaging portions surrounding each of said insulators and disposed axially between said axially spacedcircumferentially extending portions with a number of said' circumferentially extending portions engaging said polygonal-shaped portions on one axial side thereof and the remainder of said circumferential extending portions engaging said polygonah shaped portions on an axially opposite side thereof to prevent movement of said insulators relative to said frame portions in an axial direction,

the spacing between said axially extending portions 4 corresponding to the spacing between the corners of said polygonal portions and said axially extending portions being arranged at the corners of said polygonal portions to prevent rotational movement of said insulators in said polygonal frame portions.

2. The combination of claim 1' wherein said polygonal-shaped portions are formed in pairs on a continuous strip-like member and have a central web portion and formed end portions connected by said web portion, each of said end portions comprising legs arranged withadjacent legs disposed substantially at right angles to each other and closed on each other to form a closed insulator receiving opening.

3. The combination of claiml wherein said axially extending portions are equally spaced around the circumference of'said body with approximately ninety degrees therebetween,

said'polygonal-shaped insulator engaging portions are in the form of a square,

and said circumferentially extending portions extend between respective pairs of said axially extending portions with adjacent ones of said circumferentiallyextending portions being axially spaced from each other and alternate ones thereof being circumferentially aligned.

4.- An arrangement for supporting a coil of an electric heater and'comprising; in combination,

a plurality of electricalinsulators each comprising a hollow generally cylindrical body having an internal electric coil receiving opening and external radially projecting surfaces, said radially projectingysurfaces includingfirst and second circumferentially extending portions arranged on and axially spaced with respect to said body, said first and second portions being of limited circumferential extension on said body,

and frame means including generally polygonal-shaped insulator engaging portions including a plurality of leg portions, said insulator engaging portions arranged with said leg portions having limited peripheral engagement with said insulators and disposed axially between said first and second circumferentially extending portions with said first portion in engagement with said-polygonal-shaped portions on one axial side thereof and said second portion in engagement with said polygonal-shaped portions on the axially opposite side thereof to prevent relative axial movement between said insulators and said frame portions.

5. The combination of claim 4whereinsaid radially projecting surfaces also include axially extending portions spaced angularly around thecircumference of said hol-' low body, the spacing between said axially extending portions corresponding to the relative spacing between the corners of said polygonal portions and said axially extending-portions being arranged at'the corners of said polygonal portions to prevent relative rotational movement 'between' said insulators and frame portions.

6'. An insulator-frame combination for a heater and comprising,

a body of electrical insulating material having an axis, an outer periphery generated about said axis and means defining an internal coil receiving opening,

said body having at least first and second frame engaging portions extending outwardly from said periphery and relatively axially spaced on the periphery of said body with respect to eachother, said frame engaging portions having limited peripheral extensions on said body,

anda frame portion having first and second leg portions arranged axially intermediate said frame engaging portions with said first frame engaging portion engaging-said first legport'ion on one axial side thereof, said second frame engaging portion engaging said second leg portion on =an, axially-opposite side thereof and said leg portions having substantially point contact with said outer periphery.

7. The combination of claim 6 wherein said body is generally cylindrical and said first and second leg portions engage said body tangentially.

8. The combination of claim 6 including at least first and second portions projecting outwardly from said body axially intermediate said first and second frame engaging portions and arranged for engagement with respective ones of said first and second frame engaging portions to prevent relative rotational movement between said body and frame.

9. An insulator-frame combination for a heater and comprising,

a body of electrical insulating material having a longitudinal axis, an outer periphery generated about said axis and means defining an internal coil receiving opening,

means on said body projecting from said periphery and defining first radially disposed surfaces having a limited peripheral extension and relatively spaced apart from each other in an axial direction,

means on said body projecting from said periphery and defining second radially disposed surfaces relatively spaced from each other around the periphery of said body and projecting from said periphery axially intermediate said first radially disposed surfaces,

and frame means including means defining leg portions disposed at an angle to each other to define a body receiving opening and said leg portions engaging respective ones of said first portions with a number of the first portions engaging said leg portions on one axial side thereof and the remainder of said first portions engaging said leg portions on an axially opposite side thereof to prevent relative movement between said body and said frame means in an axial direction and said second portions arranged at the juncture of adjacent ones of said leg portions for engagement with said leg portions to prevent relative rotational movement between said body and frame means, said leg portions further having point contact with said outer periphery of said body at peripherially spaced points thereon.

10. The combination of claim 9 wherein said body is generally cylindrical and said leg portions define a generally polygonal body receiving opening with said legs arranged tangentially with respect to said body portion,

and said second portions have an axial extension and are relatively spaced in accordance with the spacing between the corners of said polygon and are disposed at said corners to prevent relative rotation between said body and frame means.

11. An insulator-frame combination for a heater and comprising,

a body of electrical insulating material having an axis and an internal opening and outer periphery generated about said axis,

means defining a continuous, outwardly projecting and generally undulating surface extending around said periphrey, said undulating surface including portions having a peripherally extending componnet and relatively spaced from each other in an axial direction, said undulating surface also including portions having an axially extending component and relatively spaced from each other around the periphery of said body,

frame means including leg portions arranged with adjacent leg portions at an angle to each other and closed on each other to define a closed body receiving opening, said leg portions arranged axially intermediate said axially spaced portions of said undulating surface with a number of said axially spaced portions engaging said leg portions on one axial side thereof and the remainder of said leg portions engaging said leg portions on an axially opposite side thereof, 7

and said portions of said undulating surface having an axial component being arranged at the juncture between said leg portions for engagement with said leg portions to prevent rotation of said body with respect to said frame leg portions.

References Cited UNITED STATES PATENTS 1,154,417 9/1915 Kuhn 174l38 X 1,820,696 8/1931 Forshee 338317 X 1,963,328 6/1934 Holinger 219-546 X 2,316,222 4/1943 Butters 219-532 2,478,809 8/1949 Deal 219-532 X 2,659,766 11/1953 Fot 338-299 X 2,732,475 1/1956 Averill 2l9-532 FOREIGN PATENTS 144,798 1/ 1931 Switzerland.

RICHARD M. WOOD, Primary Examiner. VOLODYMYR Y. MAYEWSKY, Examiner. 

4. AN ARRANGEMENT FOR SUPPORTING A COIL OF AN ELECTRIC HEATER AND COMPRISING, IN COMBINATION, A PLURALITY OF ELECTRICAL INSULATORS EACH COMPRISING A HOLLOW GENERALLY CYLINDRICAL BODY HAVING AN INTERNAL ELECTRIC COIL RECEIVING OPENING AND EXTERNAL RADIALLY PROJECTING SURFACES, SAID RADIALLY PROJECTING SURFACES INCLUDING FIRST AND SECOND CIRCUMFERENTIALLY EXTENDING PORTIONS ARRANGED ON AND AXIALLY SPACED WITH RESPECT TO SAID BODY, SAID FIRST AND SECOND PORTIONS BEING OF LIMITED CIRCUMFERENTIAL EXTENSION ON SAID BODY, AND FRAME MEANS INCLUDING GENERALLY POLYGONAL-SHAPED INSULATOR ENGAGING PORTIONS INCLUDING A PLURALITY OF LEG PORTIONS, SAID INSULATOR ENGAGING PORTIONS ARRANGED WITH SAID LEG PORTIONS HAVING LIMITED PERIPHERAL ENGAGEMENT WITH SAID INSULATORS AND DISPOSED AXIALLY BETWEEN SAID FIRST AND SECOND CIRCUMFERENTIALLY EXTENDING PORTIONS WITH SAID FIRST PORTION IN ENGAGEMENT WITH SAID POLYGONAL-SHAPED PORTIONS ON ONE AXIAL SIDE THEREOF AND SAID SECOND PORTION IN ENGAGEMENT WITH SAID POLYGONAL-SHAPED PORTIONS ON THE AXIALLY OPPOSITE SIDE THEREOF TO PREVENT RELATIVE AXIAL MOVEMENT BETWEEN SAID INSULATORS AND SAID FRAME PORTIONS. 